The purpose of the project was to examine measures of heart rate variability (HRV), continuously and noninvasively, in male and female alcoholics admitted for drinking cessation. The peripheral manifestations of alcohol withdrawal syndrome (AWS) are characterized by rapidly changing autonomic influences. These may vary, minute to minute and hour to hour, depending on the severity and stage of AWS. We developed measures of HRV which are relatively insensitive to non- stationarity of signal and capture relevant data during short periods of measurement. We are now analyzing data from human subjects admitted for treatment of alcohol withdrawal syndrome. Alcoholic subjects are known to have IBI time-series which are significantly less complex than healthy comparison subjects. Our question was whether abstention from alcohol use for a period of 4 to 6 weeks would result in normalization of the complexity measure back to baseline, as defined by healthy comparison subjects or if the decreased signal complexity remains stable for a period of 4 to 6 weeks. Preliminary analysis of this data shows that cardiac signal complexity increases with the length of time since the last intake of alcohol. However, even at 4 weeks, the measure does not return to the expected baseline. This suggests that either a) the length of time required for the measure to return to baseline is longer than 4 weeks, b) chronic excessive alcohol intake results in permanent autonomic disruption resulting in altered cardiac signal dynamics or c) subjects who consume excessive amounts of alcohol have a premorbid alteration in autonomic function. Of two manuscripts related to this work, one has been published and one is in press. One other manuscript is being prepared. In future work related to this project, we will address possible mechanisms of alterations in cardiac signal complexity. One major question to be answered is whether the alterations in cardiac signal dynamics we have found are associated with sub-clinical abnormalities of cardiac function. - heart, alcohol withdrawal, ethnicity, gender, signal dynamics - Human Subjects